Use of a "Moocher Hunter" to Determine a Computer's Whereabouts is not a Search Under the Fourth Amendment

In United States v. Stanley, No. 13-1910, the defendant was "mooching" off a neighbor's wireless internet router, which was not password-protected.  The officer realized this when he traced the IP address and obtained the subscriber information from Comcast, executed a search warrant at the neighbor's home, and did not find the child pornography he suspected had been downloaded from a file sharing network.  The officer then used a "moocher hunter," which is a mobile tracking software tool, to determine the whereabouts of the computer that was "mooching" off the neighbor's wireless router.

The Third Circuit held that this was not a search within the meaning of the Fourth Amendment.  The Court distinguished Kyllo v. United States, 537 U.S. 27 (2001) (the thermal imaging case), because in that case, the defendant confined his marijuana growing activities to the home.  Here, the defendant made no effort to confine his activities to his own home.  The Court reasoned that in effect, the defendant reached a "virtual arm" across the street to exploit the neighbor's internet connection.  Thus, any subjective expectation of privacy he may have had is not one society is prepared to recognize as reasonable.  The Court appeared to leave open a distinction between unauthorized wireless connections and authorized ones.

Importantly, the Third Circuit rejected the district court's finding that the defendant had no legitimate expectation of privacy because he voluntarily disclosed his signal to third parties, a rationale the Court feared "might open a veritable Pandora's Box of Internet-related privacy concerns."